Given a(z1), b(z2), and c(z3) as vertices of triangle ABC inscribed in the circle |z| = 1, where the altitude from vertex A on side BC meets the circle again at D(z4), then
A) z1z2z3z4 = 1
B) z1z2z3z4 = -1
C) z1z2z3z4 = i
D) z1z2z3z4 = -i